The ultimate "Book of Life" will be published today by scientists who have decoded a major part of the human genome, the complete genetic instructions for a human being. The occasion, however, promises to be marred by hostilities between two teams of researchers who each claim priority.

The ultimate "Book of Life" will be published today by scientists who have decoded a major part of the human genome, the complete genetic instructions for a human being. The occasion, however, promises to be marred by hostilities between two teams of researchers who each claim priority.

For the first time, scientists will be able to scan the overall map of the human genome. This promises to revolutionise medicine in the 21st century and tell us more about the evolutionary history, and possible future destiny, of humankind.

The two versions of the map, to be published in competing scientific journals as a result of the dispute between the private and public research efforts, confirm predictions that there are fewer genes than expected.

Instead of there being about 100,000 human genes, the scientists have now established that there are only some 30,000, a few thousand more than far simpler life-forms such as worms and flies. It shows that there is more to human complexity that the mere sum of our genes.

The journal Science will publish the map compiled by Celera Genomics, the US biotechnology company funded by private investors and led by Craig Venter, a former Vietnam veteran-turned-scientist-turned entrepreneur.

Nature will publish the map of the Human Genome Project, a collaboration between 16 research institutions from half a dozen countries, including Britain's Sanger Centre in Cambridge, funded by the world's biggest medical research charity, the Wellcome Trust.

The leaders of the publicly funded effort decided not to publish alongside Celera when they realised the company had imposed restrictions on how its data could be used.

Michael Dexter, the director of the Wellcome Trust, said charging fees to access the information is like charging for basic information about the chemical elements in the Periodic Table. "There are certain forms of information that should be available to everyone."

Dr Venter said that, as he has not had any taxpayer's money for his research, he has the right to protect his work. He dismissed as sour grapes claims that he could not have drawn up his own map without the help of the public map.

The new maps reveal several intriguing facts, including 223 human genes that are more similar to those found in bacteria than in other animals, suggesting that some of our genes have been directly transferred in recent evolutionary history.